The long term failure rate of total joint replacement makes it an unsuitable selection for the treatment of arthritis in the young and middle aged patient. A more appropriate treatment for these patients is a procedure that restores the joint surfaces back to their normal state with biologically competent tissues. It has been demonstrated that rib perichondrium transplanted into a joint will proliferate to form a hyaline cartilage, and that this neocartilage continues to mature until it is almost identical to the tissue it is replacing. The objectives of this proposal are to further develop a technique for grafting a large full-thickness cartilage defect in the rabbit knee femoral condyle. A systematic evaluation of different combinations of carrier and cellular source will be performed, with emphasis on allogenic demineralized bone vs porous polylactic acid as the carrier material, and perichondrial tissue vs cells derived from perichondrium in cell cultures as the cell source. Additionally, growth factors known to affect cartilage cell replication and matrix production will be tested in an in vivo model. Results of these studies will be done by using morphological, histological, biochemical and biomechanical methodologies. By following the principles of placement of an appropriate stem cell into a cartilage defect by attachment to a carrier that can be entrapped in the bone underlying the defect, we expect to develop a technique for reliable repair of human cartilage defects.